Neuro VI Flashcards
Common causes of noncommunicating hydrocephalus?
1) stenosis of aqueduct of Sylvius
2) colloid cyst blocking foramen of monro
3) tumors
Differentiating ex vacuo ventriculomegaly from hydrocephalus
ICP normal in ex vacuo ventriculomegaly
Common causes of ex vacuo ventriculomegaly
1) AD
2) advanced HIV
3) Pick disease
Total # of spinal nerves and breakdown
31 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Rules about where nerves exit
1) C1-C7 exit above corresponding vertebra.
2) C8 exits below C7 and above T1.
3) All other nerves exit below (eg C3 exits above 3rd cervical vertebra; L2 exits below 2nd lumbar vertebra)
most common locations of herniated disc
L4-L5
L5-S1
Where does spinal cord end in adults?
Lower border of L1-L2
Where does subarachnoid space extend to in adults?
Lower border of S2 vertebra.
LP location?
L3-L5, keep the cord alive.
Gracilis vs. cuneatus
Organized as you are with Arms and hands outside, legs inside.
If you see a sympathetic horn what does that tell you?
Between T1 and L2/L3
Tract locations in spinal column…
FA 472
Organization of lateral spinothalamic tract…
Sacral out wide, cervical medial.
*Legs lateral.
anterior vs. lateral spinothalamic tract
Lateral = pain, temperature anterior = crude touch, pressure.
lateral corticospinal tract organization
sacral lateral, cervical medial.
*legs are lateral
ascending vs. descending pathways
dorsal column + spinothalamic tracts carry ascending information.
CS tract carries descending information.
location of crosses in tracts
Ascending tracts (dorsal column, spinothalamic) synapse and then cross.
Dorsal column pathway
1st order neurons are sensory neurons with cell body in DRG –> enters spinal cord, ascends ipsilaterally in dorsal column –> synapses with ipsilateral nucleus cuneatus or gracilis in the medulla –> 2nd order neuron decussates in medulla –> ascends contralaterally in medial lemniscus –> synapse 2 on VPL in thalamus) –> 3rd order neuron projects to sensory cortex.
Spinothalamic tract pathway
sensory nerve ending (alpha delta or C fibers) has cell body in dorsal root ganglion, enters spinal cord –> synapse 1 in ipsilateral gray matter in spinal cord –> decussates at anterior white commissure –> ascends contra laterally –> synapses on VPL in the thalamus –> 3rd order neuron projects to sensory cortex.
Lateral CS tract pathway
UMN neurons have cell bodies in motor cortex –> descend ipsilaterally through IC –> most fibers decussate at caudal medulla (pyramidal decussation) –> descends contra laterally –> synapses on cell body of anterior horn in spinal cord –> LMN leaves spinal cord and synapses at NMJ.
**2 neuron pathway.
Weakness: UMN or LMN sign?
both
Muscle tone in UMN and LMN
Increased with UMN, decreased with LMN
spastic and flaccid paralysis for UMN and LMN
spastic paralysis = UMN lesion
flaccid paralysis = LMN lesion
syndromes affecting anterior horn?
1) polio
2) werdnig-Hoffmann
